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Comment by anonporridge | Hacker News Reader

Is California at the point now where more renewables are not just diminishing returns, but potentially negative returns due to inconsistent generation causing thrashing and large levels of curtailment required to stabilize the grid?

They're definitely causing faster natural gas generator breakdown due to them having turning up and down more frequently, causing greater wear and tear.

More batteries and demand response to stabilize the day to day grid and absorb the uncontrollable generation output is going to be increasingly necessary.

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No, because there never is such an issue. Renewables can turn themselves off and on so fast that this won't ever be a problem. The current Australian model we're discussing has about 15% 'overgeneration' because that's economically efficient, there's no problems caused by that.

What you have in mind requires someone to do the coordination. that is currently the system operator and they operate at a data rate measured in minutes or 4 s for the fastest changes (e.g. PJM).

Meanwhile, solar output can go from 100% to 10% in three seconds. How is this not a problem?

The problem anonporridge was talking about was the 10% of solar meeting the current demand and then suddenly going to 100% in three seconds, so there's 'too much' power on the grid i.e. overprovision breaking things. Which it doesn't.

While your example is solar at 100% exactly meeting demand, and then dropping to 10% in 3 seconds, and the fix for that is: overprovision (and some other stuff).

They do need to have decent predictions of demand and supply, like this graph that shows the 1-hour ahead and 24-hour ahead predictions:

https://www.caiso.com/TodaysOutlook/Pages/default.aspx

To get the whole grid working together, but we already have that, and renewables and batteries help in various ways.

PJM has "Regulation D" signals for sub-second response from energy storage resources (which are mostly batteries in practice):

https://www.pjm.com/~/media/committees-groups/task-forces/rm...

An energy storage regulating resource, such as a battery or flywheel, cannot burn fuels to produce electricity, but instead charge and discharge energy from the bulk electric system itself through a power inverter. Energy storage devices can match a desired output within 200 milliseconds of receiving the regulating signal; therefore these resources do not need to model any dynamics, ramp limitations, or dead-bands.

Australia is also using batteries in a similar way:

"South Australian Battery Responded in Just 140 Milliseconds After A Coal-Fired Power Plant Failed"

https://www.sciencealert.com/elon-musk-s-south-australian-ba...

One thing I've learned recently is that grid management is extremely primitive. People are literally emailing each other word docs and pdfs and calling each other on the phone to make changes to generation output to keep the grid stable.

It's an area that's ripe for some software innovation, if they can actually break through the legacy management club that currently runs the grid.

I, for one, can't wait for the first ever Western Interconnect black start, brought to you by an off-by-one error. During a megadrought.

There are already companies working on that https://www.emsysgrid.com/products/grid_management/futurepow...

Well, you need a 30 minute battery buffer to get gas peakers online. Whether those gas peakers are running natural gas or green hydrogen depends on how much excess solar capacity there is and how much hydrogen plants cost.

Also, medium term storage is a very, very young industry. Things like redox batteries, flow batteries, molten salt, compressed air, and many others are on the horizon. The better these work the more gas peakers are solely used as backup.

Thermal storage, like resistively heated sand, can also act as a backup source, since once the sand is exhausted they could then resort to burning something to get the heat.

Can you build out enough capacity that the lowest wind conditions during nighttime in winter don't cause outages? I worry about distribution as the answer due to the vulnerability of our existing power distribution infrastructure. Do we have answers for that yet? We need them in any case I suppose unless you build out local storage to such an extent that you don't need any grid at all even in the coldest winter or hottest summer.

You can back up the entire grid with combustion turbines burning hydrogen or some other e-fuel. A simple cycle combustion turbine power plant costs $500/kW, 20x cheaper than a nuclear plant ($10,000/kW).

Then don't you have to store the hydrogen somehow? Aren't we still working on that too?

It can be stored underground, just like millions of tonnes of natural gas already is.

It's not a technical issue, but an economic one.

If you have so much wind and solar generation that they spend too much of their lifespans sitting idle and not generating income, they potentially never even pay for their initial build cost and basic maintenance, let alone be a better investment than just buying a treasury note yielding 1%. That's a recipe for long term stagnation and depression.

Well the economic part is solved by solar/wind/batteries being much cheaper than all the other options, that's why this model overprovisions wind and solar.

So yes, lots of solar might make it more cost effective to add some wind and/or batteries and vice versa but that's a good thing and what this model explores.

If whole solar or wind farms find themselves sitting idle someone will drop off some containers nearby to split water into hydrogen or run a data center or something else that drinks power and skip the grid middle-man. Over-idle is not going to be a real issue; someone will always find a way to use of excess power.

Yeah, that's demand response.

Bitcoin miners are the key players innovating in that space right now. It's something that can very easily be packaged up in portable containers. I believe Chinese miners for years had a yearly migration to soak up massive amounts of excess hydro power during the rainy season that would have been otherwise wasted.

There might be a place for more generic computation datacenters, but they would have to find a relatively unique customer that has compute loads that can be turned off and on at a moment's notice, and potentially be down for days, weeks, and even months. There's probably a startup to be founded here, if you can figure out how to severely undercut equivalent AWS services to justify the lack of uptime guarantees.

I don't know enough about hydrogen production to know if it can be quickly spun up/down to suck up variable load. I imagine gas transport infrastructure is going to be the biggest blocker.

Over idle already is a real issue.

Who is going to build a hydrogen generator or data center with a 80% idle time, operating only 12-4 PM?

Another use is thermal batteries. Dump the power into a resistively heated mass and use that for industrial purposes. Thermal storage can be incredibly cheap per stored unit of energy.

I agree that there are solutions, I just think it is silly when people propose these high capital solutions. E.g. run a desalination plant 4 hours a day, ect.

The real solution, like you mention, is more capacity + storage. Pumped storage is my personal favorite, as it is much cheaper than batteries for anything more than 2 hours of power/day. Pumped seawater has a pretty small footprint.

Anyone for whom the ROCE is better than 1% (per the given scenario).

I doubt that data centers will be built, but there are other uses beside hydrogen -> ammonia->urea. Desalination, for instance. Carbon capture, to make money in the carbon credit markets. Even at 4 hours a day, mechanical capture with plausible costs can compete with forests.

I sincerely hope it gets there. My understanding is that carbon capture equipment isn't currently economically viable with 100% uptime

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